四川发酵香肠中乳酸菌的分离与鉴定

从四川发酵香肠中分离得到126株乳酸菌,采用透明圈法进行初筛,以发酵特性为复选指标,筛选得到2株乳酸杆菌(L1、L2)和1株乳酸球菌(P3)。对筛选出的3株乳酸菌研究其主要发酵特性,并进行产酸、耐盐和耐亚硝酸实验。结果表明,乳酸杆菌与乳酸球菌的产酸特性不同,杆菌比球菌生长快,pH下降快;3株乳酸菌对食盐和亚硝酸盐均具有较好的耐受性;对蛋白质、脂肪无明显的分解作用;对大肠杆菌、金黄色葡萄球菌有较好的抑制作用。生化鉴定以及菌株的16SrRNA测序结果表明,L1为植物乳杆菌,L2为植物乳杆菌,P3为戊糖片球菌。     

自然发酵风干肠中乳酸菌的分离与鉴定

以自然发酵风干肠为研究对象,分析了细菌总数和乳酸菌菌数的变化情况,结果表明,乳酸菌为风干肠发酵过程中的优势菌群.通过对风干肠中乳酸菌的分离鉴定,共分离出戊糖片球菌(Pediococcus pentosaceus)、乳酸乳球菌乳酸亚种(Lactococcus lactis subsp lactis)、短乳杆菌(Lactobacillus brevis)、弯曲乳杆菌(Lactobacillus curvatus)和发酵乳杆菌(Lactobacilus fermentum)5株乳酸菌.24h产酸速率测定结果表明,弯曲乳杆菌＞短乳杆菌＞乳酸乳球菌乳酸亚种＞戊糖片球菌＞发酵乳杆菌.     

渝黔地区传统酸肉发酵过程中微生物区系研究

目的:对渝黔地区传统酸肉微生物种群进行研究。方法:采用不同的选择培养基对微生物进行分离鉴定和计数。结果:从中分离出乳酸菌、酵母菌、葡萄球菌和微球菌,未发现霉菌。乳酸菌优势菌群主要是片球菌属和乳杆菌属,鉴定12株乳酸菌分别为乳酸链球菌、肠膜明串珠菌、类肠膜明串珠菌、植物乳杆菌、米酒乳杆菌、乳酸片球菌、戊糖片球菌、约氏乳杆菌、嗜盐片球菌和啤酒片球菌;优势菌株戊糖片球菌、植物乳杆菌贯穿整个发酵过程。葡萄球菌主要是表皮葡萄球菌、腐生葡萄球菌、木糖葡萄球菌和肉葡萄球菌,其中木糖葡萄球菌为主要发酵菌株。酵母菌主要为汉逊酵母属、接合酵母属、毕赤氏酵母和德巴利酵母属等,鲁氏接合酵母为优势发酵菌株。结论:优势微生物是酸肉风味品质形成的基础,本研究可为高效天然肉制品发酵剂的研究提供生物资源。     

玉米酸汤面自然发酵过程中乳酸菌的分离鉴定及特性研究

对玉米酸汤面自然发酵过程中不同时期的乳酸菌进行分离鉴定及特性研究,从中分离出5株乳酸细菌,利用现代分析技术与经典分类法对其进行了系统的细菌学鉴定.鉴定结果表明,这5株乳酸菌分别为:戊糖片球菌、乳酸乳球菌、植物乳球菌、肠膜明串珠菌、德氏乳杆菌.并测定了发酵过程中乳酸菌的数量变化及各发酵阶段的主导菌相,最后得出适宜的发酵条件.     

腊鱼加工中的乳酸菌及其特性

以白鲢为原料,对腊鱼加工过程的乳酸菌进行分离鉴定,并分析了其特性,为腊鱼加工及其品质控制提供实验数据。结果表明,腊鱼加工中存在植物乳杆菌、弯曲乳杆菌、食品乳杆菌、乳酸片球菌、戊糖片球菌,且不同加工阶段乳酸菌菌种分布不同。原料鱼、腌制结束时鱼体和成品中杆菌分别占乳酸菌的88%、56%和94%,是腊鱼加工中的优势乳酸菌。所有分离的乳酸菌都具有一定的耐盐、耐低温能力和蛋白酶活性,其中弯曲乳杆菌、乳酸片球菌的耐盐和耐低温能力较高;乳酸片球菌的蛋白酶活性最高。     

科尔沁地区传统发酵奶豆腐中乳酸菌的鉴定

从科尔沁地区采集到5份传统发酵制作的奶豆腐样中分离出12株供试菌株,将分离的菌株的16S rDNA进行PCR扩增、序列分析并构建系统发育树。结果表明,12株菌株都属于乳酸菌(Lactic Acid Bacteria),其中6株乳杆菌(Lactobacillus),分别是植物乳杆菌(Lactobacillus plantarum)4株、干酪乳杆菌(Lactobacillus casei)1株、戊糖乳杆菌(Lactobacillus pentosus)1株;6株乳球菌(Lactococcus)分别是乳糖片球菌(Pediococcus acidilactici)5株和戊糖片球菌(Pediococcus pentosaceus)1株。鉴定结果与生理生化实验结果一致,且以乳酸片球菌和植物乳杆菌为优势菌群。     

干芥菜接种发酵发酵剂优化

分别研究乳酸菌发酵剂菌株肠膜明串珠菌、植物乳杆菌和戊糖片球菌的发酵特性,并对各菌株的生长情况、产酸能力、耐盐性、耐温性及pH值适应性进行测定。结果表明,3种乳酸菌组合发酵的干芥菜总酸、氨基酸态氮、挥发酯含量和感官评分最高,此时肠膜明串珠菌∶植物乳杆菌∶戊糖片球菌=2∶3∶2,发酵产品总酸含量为1.07%,氨基酸态氮含量为0.16%,挥发酯含量为2.48 g/kg,感官评分为91.0分,品质较好,为接种发酵干芥菜的最优发酵剂。     

低盐发酵香肠用优良菌株的分离筛选及鉴定

从10 种我国自然发酵制品中分离纯化得到52 株乳酸菌及56 株过氧化氢酶阳性球菌,首先通过菌株耐受性、发酵特性等指标对菌株进行初步筛选,然后利用抑菌特性和风味特性对菌株进行复筛,选择可能改善低盐发酵香肠安全性和风味的优良菌株,最终筛选得到3 株葡萄球菌Z9、L2和R2,以及4 株乳酸菌P6、P12、X和SN1-3。经由形态学特征、生理生化特征及16S rDNA序列分析对筛选得到的菌株进行鉴定,结果表明,葡萄球菌菌株Z9、L2为腐生葡萄球菌,R2为肉葡萄球菌;乳酸菌菌株P6、P12均为植物乳杆菌,X为干酪乳杆菌,SN1-3为戊糖片球菌。最后测定菌株的生长特性及产酸能力,研究菌株间的拮抗特性,最终筛选得到戊糖片球菌SN1-3与肉葡萄球菌R2作为制作发酵香肠的复配菌株。     

传统淡水鱼发酵制品中乳酸菌的分离筛选及发酵特性

为解决我国传统淡水鱼易腐败、鱼腥味重、利用率低及附加值低等问题,对我国传统淡水鱼发酵制品中的乳酸菌进行分离鉴定及特性研究。结果表明：通过生理生化、耐盐性、抑菌性、适宜生长温度、生长曲线及pH值变化等实验筛选出的7 株乳酸菌均适宜作为淡水鱼发酵制品的发酵剂;通过16S rRNA序列分析法,确定其中2 株为戊糖片球菌,余下5 株为植物乳杆菌。     

不同乳酸菌发酵剂对发酵红肠品质的影响

为研究乳酸菌发酵对红肠品质的影响,将发酵技术应用于本无发酵工艺的红肠制品中,筛选出能够提高红肠品质的乳酸菌发酵剂。分别将常应用于发酵肉制品的7 种商业乳酸菌发酵剂（木糖葡萄球菌＋戊糖片球菌（THM-17）、木糖葡萄球菌＋清酒乳杆菌＋类植物乳杆菌（PRO-MIX5）、木糖葡萄球菌＋肉葡萄球菌＋清酒乳杆菌（WBL-45）、木糖葡萄球菌＋戊糖片球菌＋植物乳杆菌（VHI-41）、木糖葡萄球菌＋戊糖片球菌＋植物乳杆菌（SHI-59）、肉葡萄球菌＋木糖葡萄球菌（WBX-43）和戊糖片球菌＋木糖葡萄球菌＋肉葡萄球菌＋乳酸片球菌（VBM-60））及8 种单菌（弯曲乳杆菌、戊糖乳杆菌、清酒乳杆菌-1、戊糖片球菌、木糖葡萄球菌、肉葡萄球菌、清酒乳杆菌-2、植物乳杆菌）以107 CFU/g的接种量接种至腌制后的肉馅中,拌馅灌肠后于35 ℃、80%湿度条件下发酵12 h,取样测定发酵后样品的乳酸菌数和细菌总数,再经干燥、蒸煮、烟熏、烘烤制得成品,测定其感官、pH值、色差、质构、亚硝酸盐、硝酸盐、生物胺及N-亚硝胺含量等指标。结果表明：15 种发酵剂中以木糖葡萄球菌和植物乳杆菌2 种乳酸菌发酵剂应用效果较好,所制得产品pH值分别为5.26和5.04,色泽美观,弹性适中,亚硝酸盐残留量（10.84、10.13 mg/kg）低,可显著抑制N-亚硝胺的形成（N-二甲基亚硝胺含量分别为1.29、2.51 μg/kg）,生物胺总量较低。由此说明,木糖葡萄球菌和植物乳杆菌能够显著提高红肠产品的安全品质。     

金鲳鱼发酵菌株筛选及其生物学特性与风味形成评价

为了有效控制发酵鱼的品质及其保质期,从传统发酵金锠鱼中筛选适合作发酵剂的菌株。以过氧化氢酶阳性、耐盐性、抗菌性及不产生组胺为筛选指标,采用稀释分离法分离目标菌株,并对其生物学特性、发酵风味与口感进行评价。结果显示,从发酵金锠鱼中分离到的38株菌株中,筛选出的两株潜在发酵菌株（zh-b和zh-f）经形态鉴定与16S rRNA分析鉴定为戊糖片球菌（Pediococcus pentosaceus）和植物乳杆菌（Lactobacillus planta-ruma）,其最适温度分别为20与30 ℃,最适pH为5、6。两株菌对金黄色葡萄球菌与大肠标杆菌均具有抗菌活性,但植物乳杆菌抗菌活性更好,且产酸能力明显高于戊糖片球菌。电子鼻对发酵产物进行测定,发现戊糖片球菌产生的甲基类、硫化物、氮氧化合物、醇类或醛酮类和有机芳香硫化物响应值（64.10、57.98、44.75、40.22和19.93）高于植物乳杆菌（5.50、34.11、10.68、0和8.95）,是香气成分的主要贡献者。电子舌测定发现,两株菌均具有产生鲜味、鲜回味的能力,且戊糖片球菌的味值分别为14.32、6.64,明显高于植物乳杆菌产生鲜味、鲜回味（3.20、2.90）,但只有植物乳杆菌产生酸味。另外,两株菌也产生非常少量的苦味。研究为两株菌作为发酵剂用于规模化生产发酵金鲳鱼提供依据。     

农家泡菜发酵液中乳酸菌的研究

对农家泡菜发酵液中乳酸菌含量和菌种进行分析研究,经倒平板计数检测出农家泡菜发酵液乳酸菌含量为1．36×10^7cfu／mL;从农家泡菜发酵液中分离出4株乳酸菌菌株,经形态特征、菌落特征和生化特征分析,分别为植物乳杆菌、短乳杆菌、肠膜明串珠菌、戊糖片球菌。     

降亚硝酸盐乳酸菌的鉴定及生长特性的研究

从传统发酵食品中分离乳酸菌,筛选鉴定降解亚硝酸盐能力较强的菌株,并研究其在白菜汁培养基中的生长及产酸情况,为制作泡菜发酵剂储备优良菌株。结果分离了144株乳酸菌,并获得5株亚硝酸盐降解率在99%以上的菌株,经鉴定菌株Mao21.1和Mao6.2为戊糖乳杆菌,Wang3.1和Mao20.1为植物乳杆菌,Lin2.4为戊糖片球菌。5株菌在白菜汁培养基中生长4h后,各菌株培养液的pH均快速下降;培养20h后,除菌株Mao21.1外,其他菌株培养液pH均降到3.5以下;对数生长末期菌株Mao6.2和Lin2.4活菌数达到108cfu/mL,该两株菌可作为制作泡菜发酵剂的储备菌株。     

富集钙乳酸菌的筛选及培养条件对富集效果的影响

为筛选具有较强钙转化富集能力的乳酸菌（后续用于鱼骨泥发酵）,本文研究了七种乳酸菌（植物乳杆菌CY1-1、植物乳杆菌Z7、戊糖片球菌DBY2-5-1、干酪乳杆菌D400、米酒乳杆菌DL10、嗜酸乳杆菌DL12、清酒乳杆菌YP4-5）及其复合菌株的生长能力、产酸能力和钙富集能力,研究了钙离子浓度、生长时间、pH、温度对初筛菌株钙富集能力的影响,并通过原子力显微镜观察菌体富集前后的表面结构差异,研究乳酸菌的形态变化及钙离子吸附机制。结果表明,单一菌株中钙富集量最高的是植物乳杆菌CY1-1,其次为植物乳杆菌Z7。钙富集能力较强的复合菌株为CY1-1+DL12、Z7+YP4-5,富集量分别较单一菌株提高了6.76和21.69 mg/g。试验菌株在稳定期时的钙富集能力优于对数期,最适富集的钙离子浓度为1.2 mg/mL,Z7菌株的最适pH为6,Z7+YP4-5、CY1-1、CY1-1+DL12菌株的最适pH为7.2,Z7+YP4-5复合菌株的最适温度为37 ℃,其余各组菌株的最适温度为40 ℃。原子力显微镜观察到乳酸菌与钙离子结合后表面结构凸起尖锐,与未结合菌株形态差异明显。上述结果表明,钙富集能力最强的单菌株是植物乳杆菌CY1-1,复合菌株是Z7+YP4-5;乳酸菌能有效吸附钙离子在菌体表面进行富集。     

内蒙古传统发酵乳制品中乳酸菌的分离及其耐药性研究

以内蒙古通辽地区自制的奶豆腐和酸性奶油（乌日莫）为材料,采用稀释涂布法从中分离乳酸菌,通过分子生物学技术对其进行菌种鉴定,并对其耐药性进行研究。结果表明,共分离纯化得到80株乳酸菌,经鉴定,归属于13个种,分别为短乳杆菌（Lactobacillus brevis）、粪肠球菌（Enterococcus faecalis）、乳酸片球菌（Lactobacillus acidilacticii）、乳酸乳球菌（Lactococcus lactis）、瑞士乳杆菌（Lactobacillus helveticus）、屎肠球菌（Enterococcus faecium）、戊糖片球菌（Pediococcus pentosaceus）、副干酪乳杆菌（Lactobacillus paracasei）、食二酸乳杆菌（Lactobacillus digitalis）、奥塔基乳杆菌（Lactobacillus ottaki）、耐久肠球菌（Enterococcus durans）、植物乳杆菌（Lactobacillus plantarum）、开菲尔乳杆菌（Lactobacillus kefir）,表现出高的生物多样性。80株乳酸菌对萘啶酸的耐药率为100%;对链霉素、环丙沙星、万古霉素的耐药率较高,分别为95.00%、80.00%、72.50%;对利福平和四环素的耐药率中等,分别为51.25%,45.00%;对红霉素、氯霉素的耐药率较低,分别为26.25%、23.75%。此外,76株（95%）的乳酸菌还具有多重耐药性。     

南宁地区米酒曲源乳酸菌在糯米汁中氨基酸和有机酸代谢特征研究

该研究采用纯培养技术对广西省南宁地区米酒曲中乳酸菌多样性进行了解析,旨在揭示其分离株在糯米汁中产氨基酸和有机酸的特征。结果表明,11个样品共分离出20株乳酸菌,分别被鉴定为戊糖片球菌（Pediococcus pentosaceus）、融合魏斯氏菌（Weissella confuse）、类肠膜魏斯氏菌（Weissella paramesenteroides）、屎肠球菌（Enterococcus faecium）、台湾乳球菌（Lactococcus taiwanensis）、植物乳杆菌（Lactobacillus plantarum）和戊糖乳杆菌（Lactobacillus pentosus）,其中戊糖片球菌（P. pentosaceus）占分离株的35%,为南宁地区米酒曲中的优势乳酸菌。选取除屎肠球菌（E. faecium）外的16株乳酸菌分离株进行糯米汁纯种发酵,结果发现所有菌株均不产氨基酸,乳酸为糯米汁中主要有机酸。主成分分析（PCA）结果表明,融合魏斯氏菌（W. confuse）HBUAS53367产有机酸的能力较强,可用于后续进一步研究。     

Use of starter cultures of lactic acid bacteria and yeasts in the preparation of togwa,a Tanzanian fermented food

Starter cultures of lactic acid bacteria (Lactobacillus brevis, Lactobacillus cellobiosus, Lactobacillus fermentum, Lactobacillus plantarum and Pediococcus pentosaceus) and yeasts (Candida pelliculosa, Candida tropicalis, Issatchenkia orientalis and Saccharomyes cerevisiae) isolated from native togwa were tested singly or in combination for their ability to ferment maize-sorghum gruel to produce togwa. All species of bacteria showed an ability to ferment the gruel as judged by lowering the pH from 5.87 to 3.24-3.49 and increasing the titratable acidity from 0.08% to 0.30-0.44% (w/w, lactic acid) in 24 h. Yeasts used singly showed little activity within 12 h, but lowered the pH to 3.57-4.81 and increased the acidity to 0.11-0.21% in 24 h. Yeasts in co-culture with lactic acid bacteria (LAB) had a modest effect on the final acidity (P<0.05). The number of lactic acid bacteria and yeasts increased while the Enterobacteriaceae decreased with fermentation time. The pH was lowered and lactic acid produced significantly (P<0.05) fastest in natural togwa fermentation and in samples fermented by L. plantarum or L. plantarum in co-culture with I. orientalis. The content of fermentable sugars was reduced during fermentation. Most volatile flavour compounds were produced in samples from fermentation by P. pentosaceus and I. orientalis in co-culture with either L. plantarum or L. brevis.     

Characterization and selection of autochthonous lactic acid bacteria isolated from traditional Iberian dry-fermented salchichón and chorizo sausages

ABSTRACT:  A total of 192 lactic acid bacteria were isolated from 2 types of naturally fermented dry sausages at 3 different stages of the ripening process in order to select the most suitable strains as starter cultures in dry-cured sausage manufacture according to their technological characteristics such as glucose fermentation, lactic and acetic acid production, and proteolytic, lipolytic, and antimicrobial activities. Identification of the isolates revealed that 31.2% were Pediococcus pentosaceus , 26.9% Lactococcus lactis , 18.6% Pediococcus acidilactici , 17% Lactobacillus brevis , and sporadic isolates of Leuconostoc mesenteroides , Lactobacillus plantarum , and Lactobacillus curvatus . Most of the strains did not produce gas from glucose and showed the capacity to produce lactic acid rapidly. Some 25% of the strains were able to degrade tributyrin (esterase activity), but none showed lipolytic activity against olive oil and pork fat. Only 3 strains of P. acidilactici showed weak proteolytic activity against myofibrillar or sarcoplasmic proteins. Also, the same strains showed antimicrobial activity against Listeria monocytogenes . Nine strains with the best properties were preselected and tested for biogenic amine production. The results showed that two of the strains, identified as P. acidilactici by polymerase chain reaction, had the potential to be further tested as starter cultures in pilot processing of Iberian sausages.     

Characterization of lactic acid bacteria isolated from a Thai low-salt fermented fish product and the role of garlic as substrate for fermentation

Lactic acid bacteria (LAB) isolated from raw materials (fish, rice, garlic and banana leaves) and processed som-fak (a Thai low-salt fermented fish product) were characterized by API 50-CH and other phenotypic criteria. Lactococcus lactis subsp. lactis and Leuconostoc citreum were specifically associated with fish fillet and minced fish, Lactobacillus paracasei subsp. paracasei with boiled rice and Weisella confusa with garlic mix and banana leaves. In addition, Lactobacillus plantarum, Lactobacillus pentosus and Pediococcus pentosaceus were isolated from raw materials. A succession of aciduric, homofermentative lactobacillus species, dominated by Lb. plantarum/pentosus, was found during fermentation. In total, 9% of the strains fermented starch and 19% fermented garlic, the two main carbohydrate components in som-fak. The ability to ferment garlic was paralleled by a capacity to ferment inulin. An increased percentage of garlic fermenting strains was found during fermentation of som-fak, from 8% at day 1 to 40% at day 5. No starch fermenting strains were isolated during fermentation. Three mixed LAB cultures, composed of either starch fermenting Lc. lactis subsp. lactis and Lb. paracasei subsp. paracasei, or garlic fermenting Lb. plantarum and Pd. pentosaceus, or a combination of these strains were inoculated into laboratory prepared som-fak with or without garlic. In som-fak without garlic, pH was above 4.8 after three days, irrespective of addition of mixed LAB cultures. The starch fermenting LAB were unable to ferment som-fak and sensory spoilage occurred after three days. Fermentation with the combined mix of starch and garlic fermenting strains led to production of 2.5% acid and a decrease in pH to 4.5 in two days. The fermentation was slightly slower with the garlic fermenting strains alone. This is the first report describing the role of garlic as carbohydrate source for LAB in fermented fish products.